Apparatus for manufacture of cured in place liner with everted outer impermeable layer

ABSTRACT

A resin impregnated cured in place liner having an everted outer impermeable coating is provided. A roll of a continuous length of resin impregnable material is formed into a tube. An impermeable film or wrapping is formed into a tube about a tubular former, sealed and continuously everted about the inner tubular member travelling in an opposite direction so that the everted wrapping envelopes the inner tubular member. Alternatively, the inner tubular member may be passed into a stuffer tube having an impermeable tube thereon that is everted onto the moving tubular member to encapsulate the inner tubular member. The inner tubular member may be passed through an open resin impregnation tank to impregnate the impregnable material prior to everting the outer layer thereon. The inner tubular member may have an inner layer of impermeable material bonded thereto. It may be formed into a tube with the impermeable layer on the outside and continuously everted to place the impermeable layer on the inside of the tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending application Ser. No.10/704,501 filed on Nov. 7, 2003.

BACKGROUND OF THE INVENTION

This invention relates to cured in place liners for trenchlessrehabilitation of existing conduits and pipelines, and more particularlyto a cured in place liner of a resin impregnable material with aneverted outer impermeable coating or wrapping continuously manufacturedin lengths suitable for trenchless rehabilitation of existing conduitsby pulling in and inflating.

It is generally well known that existing conduits and pipelines,particularly underground pipes, such as sanitary sewer pipes, stormsewer pipes, water lines and gas lines that are employed for conductingfluids frequently require repair due to fluid leakage. The leakage maybe inward from the environment into the interior or conducting portionof the pipelines. Alternatively, the leakage may be outward from theconducting portion of the pipeline into the surrounding environment. Ineither case of infiltration or exfultration, it is desirable to avoidthis type of leakage.

The leakage in the existing conduit may be due to improper installationof the original pipeline, or deterioration of the pipe itself due tonormal aging, or the effects of conveying corrosive or abrasivematerial. Cracks at, or near pipe joints may be due to environmentconditions such as earthquakes, or the movement of large vehicles on theoverhead surface, or similar natural or man-made vibrations, or othersuch causes. Regardless of the cause, such leakages are undesirable andmay result in waste of the fluid being conveyed within the pipeline, orresult in damage to the surrounding environment and possible creation ofdangerous public health hazards. If the leakage continues it can lead tostructural failure of the existing conduit due to loss of soil and sidesupport of the conduit.

Because of ever increasing labor and machinery costs, it is increasinglymore difficult and less economical to repair underground pipes orportions that may be leaking by digging up the existing pipe andreplacing the pipe with a new one. As a result, various methods havebeen devised for the in place repair or rehabilitation of existingpipelines. These new methods avoid the expense and hazards associatedwith digging up and replacing the pipe or pipe sections, as well as thesignificant inconvenience to the public during construction. One of themost successful pipeline repair or trenchless rehabilitation processesthat is currently in wide use is called the Insituform® Process. TheInsituform Process is described in detail in U.S. Pat. No. 4,009,063,No. 4,064,211 and No. 4,135,958, the contents of which are allincorporated herein by reference.

In the standard practice of the Insituform Process an elongated flexibletubular liner of a felt fabric, foam or similar resin impregnablematerial with an outer impermeable coating that has been impregnatedwith a thermosetting curable resin is installed within the existingpipeline. In the most widely practiced embodiment of that process, theliner is installed utilizing an eversion process, as described in the'211 and '958 Insituform patents. In the eversion process, radialpressure applied to the interior of an everted liner presses it againstand into engagement with the inner surface of the pipeline as the linerunfolds along the length of the pipeline. The Insituform Process is alsopracticed by pulling a resin impregnated liner into the conduit by arope or cable and using a separate fluid impermeable inflation bladderor tube that is everted within the liner to cause the liner to cureagainst the inner wall of the existing pipeline. Such resin impregnatedliners are generally referred to as “cured-in-place-pipes” or “CIPPliners” and the installation is referred to a CIPP installation.

Conventional cured in place flexible tubular liners for both theeversion and pull-in-and-inflate CIPP installations have an outer smoothlayer of relatively flexible, substantially impermeable polymer coatingin its initial state. The outer coating allows a resin to be impregnatedinto the inner layer of resin impregnable material, such as felt. Wheneverted, this impermeable layer ends up on the inside of the liner withthe resin impregnated layer against the wall of the existing pipeline.As the flexible liner is installed in place within the pipeline, thepipeline is pressurized from within, preferably utilizing an eversionfluid, such as water or air to force the liner radially outwardly toengage and conform to the interior surface of the existing pipeline.Cure of the resin is initiated by introduction of hot curing fluid, suchas water into the everted liner through a recirculation hose attached tothe end of the everting liner. The resin impregnated into theimpregnable material then cures to form a hard, tight fitting rigid pipelining within the existing pipeline. The new liner effectively seals anycracks and repairs any pipe section or pipe joint deterioration in orderto prevent further leakage either into or out of the existing pipeline.The cured resin also serves to strengthen the existing pipeline wall soas to provide added structural support for the surrounding environment.

When tubular cured in place liners are installed by thepull-in-and-inflate method, the liner is impregnated with resin in thesame manner as in the eversion process and pulled into and positionedwithin the existing pipeline in a collapsed state. In a typicalinstallation, a downtube, inflation pipe or conduit having an elbow atthe lower end is positioned within an existing manhole or access pointand an everting bladder is passed through the downtube, opened up andcuffed back over the mouth of the horizontal portion of the elbow andinserted into the collapsed liner. The collapsed liner within theexisting conduit is then positioned over and secured to the cuffed backend of the inflation bladder. An everting fluid, such as water, is thenfed into the downtube and the water pressure causes the inflationbladder to push out of the horizontal portion of the elbow and cause thecollapsed liner to expand against the interior surface of the existingconduit. The eversion of the inflation bladder continues until thebladder reaches and extends into the downstream manhole or second accesspoint. At this time the liner pressed against the interior surface ofthe existing conduit is allow to cure. Cure is initiated by introductionof hot curing water introduced into the inflation bladder in much thesame manner as the recirculation line tied to the end of the evertingbladder to cause the resin in the impregnated layer to cure.

After the resin in the liner cures, the inflation bladder may be removedor left in place in the cured liner. Both the pull-in and inflate methodas well as the eversion method typically require man-access torestricted manhole space on several occasions during the process. Forexample, man-access is required to secure the everting liner or bladderto the end of the elbow and insert it into the collapsed liner.

Regardless of how the liner is to be installed a curable thermosettingresin is impregnated into the resin absorbent layers of a liner by aprocess referred to as “wet-out.” The wet-out process generally involvesinjecting resin into resin absorbent layers through an end or an openingformed in the outer impermeable film, drawing a vacuum and passing theimpregnated liner through nip rollers as is well known in the liningart. A wide variety of resins may be used, such as polyester, vinylesters, epoxy resins and the like, which may be modified as desired. Itis preferable to utilize a resin which is relatively stable at roomtemperature, but which cures readily when heated with air, steam or hotwater, or subjected to appropriate radiation, such as ultra-violetlight.

One such procedure for wetting out a liner by vacuum impregnation isdescribed in Insituform U.S. Pat. No. 4,366,012. When the liner hasinner and outer impermeable layers, the tubular liner may be suppliedflat and slits formed on opposite sides of the flattened liner and resininjected and on both sides as described in the '063 Patent. Anotherapparatus for wetting out at the time of installation while drawing avacuum at the trailing end of the liner is shown in U.S. Pat. No.4,182,262. The contents of each of these patents are incorporated hereinby reference.

Recent efforts have been made to modify the pull-in and inflate methodto utilize air to evert a bladder into the pulled-in liner from aproximal access point. When the everting bladder reaches the distalaccess point, steam is introduced into the proximal access point toinitiate cure of the resin impregnated into the resin impregnable layer.This process offers the advantage of faster cure due to the increasedenergy carried by the steam as the curing fluid. However, the processstill requires eversion of a bladder into the pulled-in impregnatedliner. Efforts to avoid this step of everting the bladder into thepulled-in liner include performing the eversion step above ground. Forexample, in U.S. Pat. No. 6,270,289, the process includes everting acalibration hose into a flat-lying lining hose above ground prior topulling the hose assembly into the existing conduit. This process avoidsthe eversion below grade, but is severely limited into the length oflining that can be laid out above ground prior to pulling-in.

A further suggestion to avoid this eversion is to manufacture a linerhaving an inner coating and an outer coating so that a curing fluid canbe introduced directly into a pulled-in liner. The disadvantages hereinvolves the difficulty faced when trying to impregnate the resinimpregnable material disposed between the inner and outer impermeablecoatings. The outer coating remains essential for handling theimpregnated liner and to allow the liner to be pulled into the existingconduit and the inner coating is desired to all for curing with thesteam.

Notwithstanding recent improvements in both the eversion and pull-in andinflate trenchless rehabilitation methods, both processes are laborintensive, require an eversion step and suffer from the increased costsassociated with this. Accordingly, it is desirable to provide a linermanufactured with inner and outer impermeable coatings that can bereadily impregnated to allow for curing by steam as the curing fluid totake advantage of the energy available to provide an installation methodwhich is faster and more efficient economically than currentrehabilitation methods.

SUMMARY OF THE INVENTION

Generally speaking, in accordance with the invention, a resinimpregnated cured in place liner with an inner tube of resin impregnablematerial and an everted outer impermeable coating suitable for pull-inand inflate rehabilitation of existing pipelines is provided. The linermay have an inner impermeable layer continuously formed from a length ofa resin absorbent material having bonded thereto on one surface animpermeable layer formed into an inner tubular member and sealed withthe impermeable layer on the inside of the tube. Alternatively, a tubeof resin impregnable material may be formed about a continuous tube ofan impermeable layer. The resin impregnable tube may then be wrappedwith additional layers of resin impregnable material, secured intotubular form, impregnated with a thermosetting resin and wrapped with anouter resin impermeable coating and sealed. An outer impermeable coatingor wrappings is applied to the tube by everting a tube of impermeablematerial onto the inner tubular member as it is fed into a tubularstuffer. The outer coating may be a previously formed tube orcontinuously formed and sealed prior to being everted over the innertubular member.

Accordingly, it is an object of the invention to provide an improvedmethod of cured-in-place rehabilitation of existing pipelines.

Another object of the invention is to provide an improved liner forcured in place rehabilitation of an existing pipeline.

A further object of the invention is to provide an improved liner ofresin impregnable material having an inner impermeable layer and anouter impermeable layer that has been everted over the resin impregnableinner tube suitable for trenchless rehabilitation of existing pipelines.

Yet another object of the invention is to provide an improved method ofcontinuously manufacturing a resin impregnated cured in place linerhaving an everted outer impermeable layer.

Yet a further object of the invention is to provide a method ofmanufacturing a resin impregnated cured in place liner having inner andouter impermeable layers for pull-in and inflate trenchless pipelineinstallation.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, theapparatuses embodying features of construction, combinations andarrangement of parts that are adapted to effect such steps, and theproducts that possess the characteristics, features, properties, and therelation of components, which are exemplified in the following detaileddisclosure, and the scope of the invention will be indicated in theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is had to thefollowing description taken in connection with the accompanyingdrawing(s), in which:

FIG. 1 is a perspective view of a length of a typical resin impregnablecured in place liner suitable for use in lining an existing pipeline ofthe type generally in use today and well known in the art;

FIG. 2 is a cross-section view of a cured in place liner having anintegral inner impermeable layer and an outer impermeable film orwrapping constructed and arranged in accordance with the invention;

FIG. 3 is a schematic view of the apparatus used for preparing the innerportion of the liner having an outer felt layer with an inner hightemperature polymeric layer used in connection with preparation of thecured in place liner of FIG. 2;

FIG. 4 is a cross-sectional view showing the structure of the innerportion of the liner produced by the apparatus of FIG. 3 before beingimpregnated in accordance with the invention;

FIG. 5 is a schematic in elevation showing resin impregnation of thetubular member of FIG. 4 for preparing an impregnated CIPP liner inaccordance with the invention;

FIG. 6 is a schematic in elevation showing sealing and wrapping theimpregnated tubular member exiting the resin bath in FIG. 5 with anouter coating with an edge seal placed on the inside of the outercoating in accordance with the invention;

FIG. 7 is a cross-sectional view of the edge sealer in the sealing andwrapping apparatus of FIG. 6 taken along line 7-7;

FIG. 8 is a cross-section of the liner prepared by the apparatus of FIG.6;

FIG. 9 is a schematic in elevation showing wrapping of the tubularmember exiting a resin impregnation apparatus with an outer coating bypassing the wet out liner through a tube stuffer having a tubularwrapping stored thereon; and

FIG. 10 is a cross-section of a liner wrapped by the apparatus of FIG.9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A resin impregnated cured in place liner prepared in accordance with apreferred embodiment of the invention has an integral inner lining sothat is can be installed by the pull-in-and-inflate method and inflatedand cured with a heated fluid without the use of an inflation bladder.The impregnated liner with inner impermeable polymer layer iscontinuously prepared in desired lengths. It may be impregnated as it isassembled in view of the increased effort necessary to impregnate aflattened liner having a resin absorbent material between an inner andan outer coating using convention vacuum impregnation technology.

This increased effort is necessary evidenced by the process suggested inU.S. Pat. No. 6,270,289. Here, above ground a calibration hose isinverted into a flat-lying impregnated lining hose, or an impregnatedlining hose is inverted into a tubular film using compressed air. Inthis case, the length of the lining hose approximates the length of theunderground conduit to be lined. The inversion of one tube inside theother requires an unobstructed length equal to the length of the longestlayer. If the two layers had not been previously impregnated, it wouldbe necessary to inject resin between the layers on both sides of the layflat tubes in order to provide adequate impregnation. This is adifficult and inefficient way to impregnate lining tubes. Thus, not onlyis the length restricted, but also the impregnation is extremelydifficult.

FIG. 1 illustrates a flexible cured in place liner 11 of the typegenerally in use today and well known in the art. Liner 11 is formedfrom at least one layer of a flexible resin impregnable material, suchas a felt layer 12 having an outer impermeable polymer film layer 13.Felt layer 12 and outer polymer layer 13 are stitched along a seam line14 to form a tubular liner. A compatible thermoplastic film in a form ofa tape or extruded material 16 is placed on or extruded over seam line14 in order to ensure the impermeability of liner 11. In the embodimentillustrated in FIG. 1 and used throughout this description, liner 11includes an inner tube of a second felt layer 17 also stitched along aseam line 18 positioned at a point in the tube other than the locationof seam line 14 in outer felt layer 12. Outer felt layer 12 with polymerlayer 13 is then formed around inner tubular layer 17. Afterimpregnation liner 11 in a continuous length is stored in arefrigeration unit to suppress premature cure of the resin. Liner 11 isthen cut to a desired length after being pulled into the existingpipeline, or is cut prior to being everted into the existing pipeline.

Liner 11 of the type illustrated in FIG. 1 is impermeable to water andair. This will allow use in an air or water eversion as described above.However, in a pull in and inflate installation in accordance with theinvention, the outer coating on the liner need only be sufficientlyimpermeable to allow for easy handling and retention of resin and toprevent damage to the liner as it is pulled into the existing pipeline.

For larger liner diameters, several layers of felt or resin impregnablematerial may be used. Felt layers 12 and 17 may be natural or syntheticflexible resin absorbable material, such as polyester, acrylicpolypropylene, or inorganic fibers such as glass and carbon.Alternatively, the resin absorbent material may be a foam. Impermeablefilm 13 may be a polyolefin, such as polyethylene or polypropylene, avinyl polymer, such as polyvinyl chloride, or a polyurethane as is wellknown in the art. Any form of sewing, adhesive bonding or flame bonding,or any other convenient means can be used to join the material intotubes. In the initial step in all trenchless rehabilitationinstallations, the existing pipeline is prepared by cleaning andvideotaping.

Referring now to FIG. 2, a cured in place liner 21 prepared inaccordance with the invention is shown in cross-section. Liner 21similar to convention liner 11, but includes an inner impermeable layer22 that has a thin felt or resin impregnable layer 23 bonded thereto.Inner felt layer 23 has been sewn along the longitudinal edges to form aseam line 24 by a row of stitches 26 and sealed with a tape 27 appliedover stitches 26. An outer felt layer 28 is wrapped about inner thinfelt layer 23 and formed into a tube by stitches 29. Finally, an outerlayer or wrapping 31 is formed into a tube with an edge seal 32 andcontinuously everted over outer felt layer 28 so that an edge seal 32 isencapsulated under outer impermeable layer 31 as will be described inmore detail below.

By manufacturing a liner in this manner, it is not necessary to evertthe liner during installation or evert an inflation bladder after theliner has been pulled into the existing conduit. Thus, significantsavings in labor cost at the time of installation are available. It alsoallows for use of a heated curing fluid such as steam to inflate andcure the resin. In such case all the heated fluids are introduced intothe liner below grade level to provide a safer work environment.

Felt layers 23 and 28 may be impregnated in the usual manner usingvacuum. Alternatively, felt layers 23 and 28 are first impregnated withresin and then an outer impermeable layer 31 is applied. This avoids thedifficulty with impregnating a finished liner having felt layers betweenan inner and outer impregnable layer. In U.S. Pat. No. 4,009,063, EricWood proposed injecting resin in the felt layer using needles insertedinto opposite sides of a flattened constructed liner. This operationrequires cutting and patching needle holes in the outer coating. Thevacuum impregnation process taught in U.S. Pat. No. 4,366,012 would notbe suitable unless the vacuum is drawn on both sides as the innercoating is a barrier to resin flow in a liner with inner and outercoating. In order to overcome the impregnation difficulties, liner 21 ismanufactured from endless rolls of flat coated and plain felt andcontinuously impregnated prior to application of outer wrapping 31. Thismay be accomplished by the method using the apparatuses illustrated inFIGS. 3, 5, and 6 resulting in a liner 74 as illustrated in FIG. 8.

While felt layers 23 and 28 are formed into tubes by stitching and/ortaping, any of the conventionally known methods for forming felt orother resin impregnable material into tubes is suitable. For example,tubes can be formed by use of various glues or adhesives as well asflame bonding. Tape may be applied to inner impermeable layer 22 byapplying an adhesive strip or extruding a layer of polymeric material inorder to seal the butted edges of the felt material and the holes formedduring a sewing operation.

Referring now to FIG. 3, a method for continuously forming a length of atube or resin impregnable material with a sealed inner impermeable layeris shown. A roll of coated felt 36 having a continuous length of felt 37with an impermeable layer 38 is fed over a directional roller 39 in flatform with coated side facing roller 39 to a tube forming device 41.

Tube forming device 41 includes a tubular support frame 42 having aproximal end 42 a and a distal end 42 b and a film deformer 40. Aseaming device 43 that may be a sewing and taping machine, gluingmachine or flame bonding apparatus is mounted above support frame 42.Felt 37 with impermeable layer 38 facing roller 39 is fed in thedirection of an arrow A to the proximal end of tube forming device 41where it is deflected by deflector 40 and wrapped around support frame42 and seamed into a tube 44 along a seam line 46 with felt 37 on theinside and impermeable layer 38 on the outside. Tube 44 then passes ataping device 47 where a tape 48 is placed over seam line 46 to form animpermeable coated taped tube member 45.

Tube 44 then continues to travel along tubular support frame 42 to aninverter ring 49 at a distal end 42 b of support frame 42. Taped tube 45is then everted into tubular support frame 42 so that impermeable layer38 is now on the inside of tube 45 as it is withdrawn from the proximalend 42 a of tubular support frame 42 along a line defined by an arrow B.At this point everted tube 45 has the structure illustrated incross-section in FIG. 4 with impermeable layer 38 on the inside and feltlayer 37 on the outside. Tube 45 is then stored for further use or maybe passed directly to a resin impregnation step as shown in FIG. 5 priorto final wrapping.

FIG. 5 illustrates in schematic impregnation of a supply 51 of tapedtube 45. Here, tube 45 is pulled in arrow direction C by or through apair of rubber covered pulling rollers 52 into an open top resin tank 53filled to a predetermined level with a curable thermoset resin 54 toform an impregnated or wet-out tube 55. Tube 45 passes between a firstand second set of compression rollers 56 and 57 and around a firstdirectional roller 58 to turn tube 45 in a horizontal direction and asecond directional roller 59 to turn tube to a vertical direction. Asonic wave generator 61 may be utilized in lieu of or in addition tosecond compression rollers 57. Sonic wave generator 61 improves theimpregnation of resin 54 into felt layer 37 of tube 45 as it passesthrough resin tank 53. After changing direction about second directionalroller 59, impregnated tube 55 with resin passes between a pair ofpneumatic calibration rollers 62. At this time, tube 55 then entersthrough a film wrapping and sealing station shown generally as 63 in thedirection of arrow D.

Film wrapping and sealing station 63 shown in FIG. 6 includes a formerpipe 64 having an inlet end 64 a and an outlet end 64 b and an edgesealer 65 positioned above the mid-section of former pipe 64. A roll 66of a resin impermeable film material 67 that is to be wrapped aboutimpregnated tube 55 fed into former pipe 64. Resin impermeable filmmaterial 67 is fed from roll 66 about a series of direction rollers 68a-e and pulled by a pair of drive rollers 69 a and 69 b as film 67 isfed over rollers 70 a-d to former pipe 64. A deflector 71 at outlet end64 b of former pipe 64 directs film 67 about former pipe 64 prior tobeing fed into edge sealer 65 to form film 67 into a tube 72 with anedge seal 73 extending outwardly therefrom. Tube 72 of impermeablematerial moving along former pipe 64 is pulled in a direction indicatedby an arrow E to inlet end 64 a of former pipe 64 whereupon tube 72 iscontinuously everted into the interior of former pipe 64 and ontoimpregnated tube 55 and pulled in the opposite direction indicated by adashed arrow F.

At this time impregnated tube 55 exiting open resin bath 54 is fed inthe direction of arrow D into inlet end 64 a of former pipe 64 and isenveloped by everting film tube 72. As film tube 72 is everted, edgeseal 73 is displaced to the inside of tube 72 so that edge seal 73 isdisposed between impregnated tube 55 and film tube 72. A wrapped wet-outCIPP liner 74 including wet-out tube 55 and everted film tube 72 ispulled out outlet end 64 b of former pipe 64 by a pair of drive rollers79 and 81. Alternatively, liner 74 may be withdrawn by a pair oftractors or a driven conveyor belt and fed to a refrigerated truck forstorage and shipment to an installation site.

Referring to FIG. 7, a cross-sectional view through edge sealer 65 andformer pipe 64 along line 7-7 in FIG. 6 is shown. Edge sealer 65 formsedge seal 73 in film tube 72 as film tube 72 passes over the outside offormer pipe 64. Once tube 72 is everted, edge seal 73 is now insidewrapped wet-out tube 74 as it is pulled from outlet end 64 b of formingpipe 64. Outer impermeable film 72 may be applied prior to or afterwet-out. In the case where this is prior to wet out, tube 45 prepared asshown in FIG. 3 is fed directly to tube forming assembly 67 in FIG. 6and provides liner 74 shown in cross-section in FIG. 8.

Referring now to FIG. 9 an alternative apparatus for wrapping an outerimpermeable tube 81 about impregnated tube 55 is shown generally as 82.Here tube 45 may be impregnated in the same manner as described inconnection with wet-out tank 53 in FIG. 5 and then tube 55 is fed into astuffer pipe 83 having an inlet end 83 a and an outlet end 83 b.Reference numerals as used in FIG. 5 are applied to identical elementshere.

A supply of a flexible impermeable tube 81 is loaded onto the outsidesurface of stuffer pipe 83 having an inlet end 83 a and an outlet end 83b. Impregnated tube 55 leaving resin tank 53 is fed into inlet end 83 aof stuffer pipe 83. As tube 55 enters inlet end 83 a of stuffer pipe 83,impermeable tube 81 is pulled off the outside of stuffer pipe 83 andeverted about inlet end 83 a into the inside of stuffer pipe 83 toenvelope impregnated tube 55 as it leaves outlet end 83 b. This forms acomplete liner 86 having inner impermeable layer 38 and outerimpermeable coating 81. Tube 86 with outer coating 81 is removed fromoutlet end 83 b of stuffer tube 83 by a pair of drive rollers 87 and 88,or other pulling device such as tractors or a conveyor, in a directionof an arrow F′. When an extruded tube is used in this embodiment, thereis no seam in outer impermeable coating 81. The sole limitation ofpreparing tube 86 in this manner is the length of impermeable tube 81that can be placed on stuffer tube 83. It has been found that about1,000 feet of an impermeable tube can be compressed onto a stuffer tubeof about 20 feet in length. Longer lengths can be stored on longerstuffer tubes.

FIG. 10 is cross-section of liner 86 as it exits stuffer tube 83. Liner86 includes inner tubular member of resin absorbent material 37 havingan impermeable inner coating 38 sealed with a tape 48 as described inconnection with FIG. 4. After exiting stuffer tube 83, liner 86 includesouter tubular wrapping 81. In view of the fact that tubular wrapping 81is a previously extruded tube, outer wrapping 81 does not have any seamsas in connection with FIGS. 6 and 8.

Once at the installation site, wrapped impregnated tube 74 or 86 havinginner impermeable layer 38 and outer impermeable wrapping 72 or 81 isready for installation by the pull-in-and-inflate method. This method isfully described in U.S. Pat. No. 4,009,063, the contents of which areincorporated herein by reference. In the case of installation by thepull-in-and-inflate method, a separate eversion bladder is not necessaryto inflate the liner due to the presence of inner impermeable layer 38.By proper selection of materials for inner impermeable layer 38, such aspolypropylene, inflation and curing can be done with steam introducedinto liner 74 or 86 once in position in the existing conduit.

The processes and apparatuses described herein provide a convenientmeans to prepare a cured in place liner having both inner and outerimpermeable layers. A tube forming and eversion apparatus as illustratedin FIG. 3 readily provides a method to prepare the inner portion of thefinished tube with an impermeable layer on the inside of the tube and anouter felt layer. Additional layers of uncoated felt may be wrappedabout the formed inner tube if desired.

An inner tubular member for a CIPP liner prepared in accordance with theprocess described in connection with FIG. 3 can be readily impregnatedin an open top resin tank and enveloped within an impermeable wrappingas described in connection with the apparatus shown in FIG. 6 or in FIG.9. By continuously forming an outer wrapping with an edge seal andcontinuously everting the sealed film tube about a wet-out tube, theseal is inverted provided a wrapped wet-out tube with a smooth outersurface ready for pull-in-and-inflate installation. Similarly, byeverting a tube over the inner tube, a smooth outer surface is alsopresented to the conduit to be lined.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in carrying out the above process, inthe described product, and in the construction(s) set forth withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description and shown in theaccompanying drawing(s) shall be interpreted as illustrative and not ina limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

1. An apparatus for wrapping a cured in place liner with an evertedouter tubular impermeable wrapping, comprising: a supply holder forholding a length of an impermeable material; a tubular section having anopen inlet end and an open outlet end; a sealing section for sealing thelength of impermeable material into a tube about the distal end of thetubular section and everting the tube of impermeable material into theinlet end to envelope an inner tubular member; and pulling means forwithdrawing the wrapped inner tubular member as the wrapping is evertedabout the inlet end of the tubular section.
 2. The wrapping apparatus ofclaim 17, wherein the outlet end of the tubular section is open at theupper portion thereof.
 3. The wrapping apparatus of claim 18, whereinthe opening includes an inclined section.
 4. The wrapping apparatus ofclaim 18, wherein a sealer is disposed over the open proximal end of thetubular section.
 5. The wrapping apparatus of claim 18, wherein thesealing section is an edge sealer.
 6. An apparatus for wrapping a curedin place liner with an everted outer tubular impermeable wrapping,comprising: a tubular supply holder for holding a tubular length of animpermeable material; the tubular holder having an open inlet end and anopen outlet end adapted to invert the tube of impermeable material intothe inlet end to envelope an inner tubular member moving therethrough;and pulling means at the outlet end of the tubular holder forwithdrawing the wrapped inner tubular member as the wrapping is evertedabout the inlet end of the tubular section.